User blog:Unin/FrodoTip: Nukes?
This will hopefully be one of a series of articles meant to address common Frodo complaints. Caution: Occasional injects of real world physics, possibly involving maths, may be involved. FRODO: Why don't they just use nukes? The usual retort to this is some combination of "Missiles Haet Lasers" and "Japan Haet Nukes". To an ignorant Frodo, the first is usually sufficient. In short, the laser class renders most nuclear warhead delivery systems useless. While America was able to nuke the BETA attempt at a North American Hive, that was only because America's "nuke first; ask questions later" policy managed to wipe out the hive attempt before any Lux class could be fielded. This does not mean that unconventional warhead delivery methods that could deploy a nuke don't exist, but normal tactics don't work. The second response is just plain wrong. Remember, in the Alterniverse Japan was never nuked (Germany was instead); there's no basis or trauma for Japan to have any nuclear aversion, and the use of heavy metal clouds and depleted uranium ammo suggests long-term environmental damage isn't much of a concern for the powers that be. Once you throw MAD politics out the window, nukes are fundamentally offensive weapons. While an argument could be made for deploying minefields, this is really only effective if you can predict your opponents movements. For the BETA, the utility provided by an explosive weapon of mass destruction is relegated to eliminating large mobs and clearing out hives. A nuke might seem ideal for this against human enemies, but the properties that make it dangerous against humans do not necessarily translate as effective against BETA. While we know very little about BETA physiology, we do know they can survive unaided on the surface of the moon and Mars, as well as traverse ocean floors. This implies an innate resistance to ionizing radiation, as well as tolerance of relatively extreme temperatures and pressures. While a BETA species at ground zero of a nuclear detonation would certainly take lethal damage, a nuke may not be as effective at clearing masses of BETA as one would assume. While the largest nuclear weapon detonated in the real-world, Tsar Bomba, had a yield of 50 Megatons, it also weighed 60 thousand pounds and was half the size of a TSF. For purposes of this discussion, a modest 1 MT device is assumed, for logistical practicality. Upon detonation, more than 4 Petajoules of energy is released, however most of the energy is released in the form of UV and X-ray radiation. The atmosphere is mostly opaque to these wavelengths, and begins to absorb it as heat, reaching a temperature of up to 1 million Kelvin. However, as the air ionizes it eventually becomes transparent to these wavelengths, allowing the radiation to propagate outwards spherically as the cloud of ionized atmosphere expands. This causes a dramatic drop in temperature at the cube of the distance from ground zero. If we assume the maximum surface temperature of the moon is the maximum tolerable temperature exposure for BETA (an upper limit with no actual basis, but generously low for the sake of argument), then all BETA within a maximum of 4000 ft from ground zero are exposed to temperatures in excess of 390K, and perhaps expire. If we assume the BETA distribution during Operation 21ST is average for BETA herds (again generous given proximity to a hive), than a Battalion size Herd of BETA can be spread over an area perhaps a dozen miles in radius, requiring roughly 150 - 1MT warheads evenly distributed to saturate the area to a lethal temperature for a few seconds just on thermal radiation alone. 150 warheads to wipe out a battalion sized herd... maybe. This lasts for 4 to 5 seconds before the hot air begins to rise away from the surface (sucking in cooler air), and within 20 seconds (decreasing with increased pressure zones) the air returns to normal. If the BETA had lungs, they would be cooked, but considering the fact that they're space monsters, that probably wouldn't be an issue. 20 seconds isn't a lot of time for thermal conduction to transfer the energy from hot air to BETA either, and initial radiation may actually induce protective ablation, insulating quite a bit. This is all assuming an air-burst, which would be difficult with any Lux around; for surface detonations you can approximately half the energy densities. This also assumes an ideal flat surface, with clear air. Heavy Metal clouds in the area would obviously reduce the thermal load via reduced radiation transmittance. The next "deadly" threat nuked BETA would be exposed to is nuclear radiation. Neutron flux can be expected to decrease at the inverse square of the distance (ignoring air absorption and capture, which to be fair may result in gamma rays), while equivalent radiation dosages would depend on the distribution of radioactive isotopes after the blast. For the most part, anything within 1.2 miles of the blast would be subjected to in excess of 1000 rem. For perspective, 600 rem is 100% fatal for humans, but 1000 rem is just a particularly "sunny" day for BETA strolling on the surface of the moon. If we assume 1000 rem is the absolute limit for BETA however (again exceedingly generous), then it would take only 100 warheads to wipe out that herd. Getting better, but still prohibitive, and that's at an arbitrarily low tolerance. It should be noted that rem exposure is a cumulative thing, but BETA aren't exactly likely to sit around and wait to be evenly cooked post detonation. Radiation absorbed dose falls off even faster with distance, so we can ignore it. Perhaps the pressure from the air blast would be more effective? In terms of blast overpressure for humans, 4psi can be lethal in terms of respiratory and circulatory damage. 10 psi is comically lethal, involving dismemberment, and is even strong enough to bust up reinforced concrete. But BETA body-slam through reinforced concrete all day, with no ill effects, and modern bomb-suits can use rigid plates to deflect such overpressure to non-lethal levels. That said, lets call 10 psi the upper limit for BETA overpressure. Everything inside of bout 8000ft from the blast experiences at-least that pressure at some point, generally within the first few seconds, though its obviously a quick peak that falls once the wave passes. Pressure actually falls to significantly below atmospheric, causing a short suction event, but not significant as far as BETA are concerned (vacuum is fine too). the 500mph wind might pick up and toss around tank class and smaller, but critters like these, with an arm-strength capable of equally comic dismemberment as that blast overpressure, ought to be able to hold on for those few seconds given a good grip. But still, an assumed lethality radius of 8000 ft requires only 50-60 1MT blasts to wipe out that herd. These numbers might be feasible for planning a nuclear minefield, if BETA could be relied on to chose such a path to frolic and scamper through, however BETA are notoriously unpredictable, and the number of nuclear warheads needed to adequately form a defensive line simply isn't practical. Big nukes, that could get the job done in one detonation, are too big to lug around, too expensive to field, and take a lot of resources to mass produce. Nukes might have a small offensive role in clearing out hives, but only if you can get deep enough into the hive in the the first place to make it worth while (drift entrances could be just as easily cleared with cheaper air-fuel bombs). Once humanity had the capability to penetrate hives that deep, G-bombs were already available and mass producible. We don't know much about G-bombs. The G stands for Gray, though it's implied gravity plays a role, but one thing that's made clear is that advances in Moorcock-Lechte technology have made them cheap and easy to mass produce. 2 G bombs are presumably enough to level a phase 2 monument and clear out most of the hive's upper stratum. It is unclear whether G-bombs are an explosion or implosion; some have proposed that they are actually temporary black holes, suggested by what little G-bomb art we have, and the fact that they are caused by run-away gravity engines. An implosion however would be inconsistent with the predicted Tsunami's the XG-70b created upon overload. (The rebound force of water back washing into a Sadogashima sized hole in the ocean is not sufficient). Whatever means of destruction G-bombs wrought, The ability to turn a 330 square mile island into an equal if not larger sized crater beneath the ocean is currently outside the means of any warhead currently available. It's destructive power appears to be roughly constant up to a particular threshold distance, rather than weakening exponentially with distance, killing anything within that radius (except the occasional brain). It would not be unreasonable to suggest that a single G-bomb could, under merely average circumstances, take out an entire battalion sized herd. Other nuke issues: But wait! Compton Scattering! EMP! surely that's got to- oh wait, dealing with zerg, not terrans. never mind. Maybe nukes could be used to dig to hive reactors!? 1 MT in hard rock - 100 Ft crater, and that's if it's adequately plugged. A constrained detonation also takes longer to cool, reducing rate of excavation further, unless your nukes are lava-proof. Couldn't the ground shock be used to collapse a hive? Reduces at the cube of the distance, and is slower than initial vaporization, such that the pressure wave has to travel through vaporized gas before encountering solid ground, losing energy at the boundary. It also further weakens as it transitions between rock strata, due to scattering, rebound, and interference. Well the fallout could still deny BETA territory! Compared to the lunar surface, fallout strew-fields are just fine. sources: *http://www.dtic.mil/cgi-bin/GetTRDoc?AD=AD601139 *http://www.fas.org/nuke/intro/nuke/7906/790604.pdf *http://www.ncbi.nlm.nih.gov/pubmed/8606389 *http://www.rcktmom.com/njlworks/LunarRegolithPprenvi2.html *http://settlement.arc.nasa.gov/Contest/Results/96/winner/cuatro.html Category:Blog posts Category:FrodoTip